The degradation of parathion and DDT in aqueous systems containing organic additives

Laboratory studies were conducted to investigate some of the factors influencing pesticide degradation in aqueous systems. parathion added to natural water in ethanol, acetone or without organic solvent, was completely degraded within 2 wk. While most of the parathion was reduced to amino-parathion when added in ethanol, no amino-parathion was detected in the presence of acetone or when no solvent was added, suggesting that in the latter two cases the insecticide was aerobically degraded to other metabolites. No paraoxon was detected. When ethanol concentration was increased from 1% to 2 and 4%, the rate of parathion degradation was inversely related to the ethanol concentration. In the presence of glucose as a carbon source, approximately 50% of the parathion was reduced to aminoparathion. DDT degradation in natural water was more rapid when it was added in ethanol than when added in acetone. The only DDT metabolite detected was TDE, with about 36% conversion in presence of ethanol, and 20% when the DDT was added in acetone.